Study: A blend of plant oils proves effective for growth and feed efficiency in piglets

Mixed plant oils containing 10% coconut oil, 15% corn oil, 15% linseed oil, 15% peanut oil, 20% palm oil, and 25% soybean oil or these mixed plant oils combined with extruded corn are more effective than soybean oil alone as a lipid source in improving growth performance, serum immunity, antioxidant capacity, apparent total tract digestibility of ether extract and intestinal morphology in piglets, found Chinese researchers.  

The paper was published in the journal, Animal Feed Science and Technology​​.​

Background ​

Weanling piglets are easily prone to weaning stress due to the sudden changes of environment, nutrition and psychology, and such stress can cause a decrease in digestive enzyme activity, feed intake and growth performance, said the authors.

The rapidly decreased activities of pancreatic lipase and pancreatic digestive enzymes may also reduce digestion and absorption of energy feeds, such as animal fats and plant oils (Gu and Li, 2003).

Therefore, adding lipids, including animal fats and plant oils, to swine diets can not only help supply concentrated energy, highly digestive essential fatty acids and fat-soluble vitamins, but also increase the palatability of the swine diet and therefore improve the feed efficiency and intestinal health for weanling piglets (Pettigrew et al., 1991; Rossi et al., 2010), explained the research team.

Moreover, monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) in animal fats or plant oils also have nutritional and physiological effects and could help alleviate weaning stress in early weaning piglets (Zentek et al., 2011), they noted.

Although there are many studies showing how variety in fatty acid composition in plant oils, such as saturated fatty acid (SFA) and unsaturated fatty acids, can affect the nutrient digestibility and performance for post-weaning piglets (Wiseman et al., 1990), there are few studies focused on finding novel effective combinations of high-quality plant oils, and their effects on performance, nutrients digestibility, and intestinal health in piglets after weaning.

“The aim of this study was to evaluate the effect of two [sets of] novel mixed plant oils on performance, serum immunity, antioxidant capacity and intestinal morphology in weanling piglets compared with soybean oil (SO).”​

Methodology ​

A total of 108 piglets, weaned at 28 days, were randomly allotted into one of three dietary treatments with six replicate pens per treatment, three barrows and three gilts per pen, said the team.

The study contained two feeding phases - phase 1 (day 0–14) and phase 2 (day 14–28), they added.

Dietary treatments included

• a control diet (CON; corn-soybean meal basal diet + 5% SO in phase 1 or 4% SO in phase 2),
• a mixed plant oil 1 diet (MPO1; basal diet + 5% MPO1 in phase 1 or 4% MPO1 in phase 2; a mixture of 10% coconut oil, 15% corn oil, 15% linseed oil, 15% peanut oil, 20% palm oil, and 25% SO), and
• a mixed plant oil 2 diet (MPO2; basal diet + 5% MPO2 in phase 1 or 4% MPO2 in phase 2; a mixture of half MPO1 and half extruded corn)

Findings ​

Compared with the control, the piglets fed MPO (MPO1 or MPO2) had increased average daily gain (ADG) and feed efficiency in phase 1 and, overall, as well as improved serum superoxide dismutase (SOD) content on day 14, reported the researchers.

Those piglets also had higher serum IgG, serum superoxide dismutase (SOD), glutathione peroxidase contents, villus height in duodenum and jejunum, and apparent total tract digestibility (ATTD) of ether extract on day 28, they said.

Piglets fed MPO2 showed a higher IgM content on day 14 and growth hormone content in serum on day 28 compared with piglets in the control group, they added.

In conclusion the team found mixed plant oils (MPO) increased average daily gain and feed efficiency compared with soybean oil in weanling piglets, improved antioxidant status and serum immunity compared with soybean oil in the animals, ​increased intestinal morphology compared with soybean oil and provided a better 'energy feed' than a soybean oil based diet for weanling piglets.

Weighing in on their findings, the team commented:

“The improved growth performance may also relate to the improvement of intestinal morphology. The current study showed the intestinal morphology, especially the villus height in duodenum and jejunum, was improved in piglets fed MPO, which probably reflects the improvement of nutrient digestion and absorption capacity of small intestine in piglets (Xiong et al., 2015)."​

After weaning, the epithelial structure and integrity of piglets are mainly affected by the sudden feed composition change and an increased rate of cell apoptosis (Van der Peet-Schwering et al., 2007), they added.

“Therefore, weaning piglets may face severe reduction in villus height, which can decrease the ability to absorb nutrition since the intestinal villi are the site for nutrient absorption. The improved intestinal morphology may be the reason that MPO can decrease pathogenic bacteria in the gut of weanling piglets, which may help improve proliferation of epithelial cells to build villus (Mourao et al., 2005).​

“Moreover, MPO may also improve intra-epithelial lymphocytes and local immune defense, and therefore improving the intestinal morphology in weanling piglets. Another explanation of our present results may be due to that MCFA in MPO can provide rapidly available energy for intestinal and extra-intestinal tissues in weanling piglets (Heo et al., 2002),” ​commented the research team.

Source: Animal Feed Science and Technology ​

DOI: https://doi.org/10.1016/j.anifeedsci.2019.114337​​

Title: Dietary mixed plant oils supplementation improves performance, serum antioxidant status, immunoglobulin and intestinal morphology in weanling piglets​

Authors: SF Long, TF He, Li Liu, XS Piao